Ternary azeotropic compositions of 43-10mee (CF3 CHFCHFCH2 CF.sub.

ABSTRACT

Azeotropic mixtures of 1,1,1,2,3,4,4,5,5,5-decafluoropentane and trans 1,2-dichloroethylene with methanl or ethanol, the azeotropic mixtures being useful in solvent cleaning applications.

INVENTION BACKGROUND

As modern electronic circuit boards evolve toward increased circuit andcomponent densities, thorough board cleaning after soldering becomes amore important criterion. Current industrial processes for solderingelectronic components to circuit boards involve coating the entirecircuit side of the board with flux and thereafter passing theflux-coated board over preheaters and through molten solder. The fluxcleans the conductive metal parts and promotes solder fusion. Commonlyused solder fluxes generally consist of rosin, either used alone or withactivating additives, such as amine hydrochlorides or oxalic acidderivatives.

After soldering, which thermally degrades part of the rosin, theflux-residues are often removed from the circuit boards with an organicsolvent. The requirements for such solvents are very stringent.Defluxing solvents should have the following characteristics: a lowboiling point, be nonflammable, have low toxicity and high solvencypower, so that flux and flux-residues can be removed without damagingthe substrate being cleaned.

While boiling point, flammability and solvent power characteristics canoften be adjusted by preparing solvent mixtures, these mixtures areoften unsatisfactory because they fractionate to an undesirable degreeduring use. Such solvent mixtures also fractionate during solventdistillation, which makes it virtually impossible to recover a solventmixture with the original composition.

On the other hand, azeotropic mixtures, with their constant boilingpoints and constant compositions, have been found to be very useful forthese applications. Azeotropic mixtures exhibit either a maximum orminimum boiling point and they do not fractionate on boiling. Thesecharacteristics are also important when using solvent compositions toremove solder fluxes and flux-residues from printed circuit boards.Preferential evaporation of the more volatile solvent mixture componentswould occur if the mixtures were not azeotropic and would result inmixtures with changed compositions, and with attendant less-desirablesolvency properties, such as lower rosin flux solvency and lowerinertness toward the electrical components being cleaned. The azeotropiccharacter is also desirable in vapor degreasing operations, whereredistilled solvent is generally employed for final rinse cleaning. Insummary, vapor defluxing and degreasing systems act as a still. Unlessthe solvent composition exhibits a constant boiling point, i.e., is anazeotrope fractionation will occur and undesirable solvent distributionswill result, which could detrimentally affect the safety and efficacy ofthe cleaning operation.

A number of chlorofluorocarbon based azeotropic compositions have beendiscovered and in some cases used as solvents for solder flux andflux-residue removal from printed circuit boards and also formiscellaneous degreasing applications. For example: U.S. Pat. No.3,903,009 discloses the ternary azeotrope of1,1,2-trichlorotrifluoroethane with ethanol and nitromethane; U.S. Pat.No. 2,999,815 discloses the binary azeotrope of1,1,2-trichlorotrifluoroethane and acetone; U.S. Pat. No. 2,999,817discloses the binary azeotrope of 1,1,2-trichlorotrifluoroethane andmethylene chloride.

Such mixtures are also useful as buffing abrasive detergents, e.g., toremove buffing abrasive compounds from polished surfaces such as metal,as drying agents for jewelry or metal parts, as resist-developers inconventional circuit manufacturing techniques employing chlorine-typedeveloping agents, and to strip photoresists (for example, with theaddition of a chlorohydrocarbon such as 1,1,1-trichloroethane ortrichloroethylene). The mixtures are further useful as refrigerants,heat transfer media, gaseous dielectrics, foam expansion agents, aerosolpropellants, solvents and power cycle working fluids.

Closed-cell polyurethane foams are widely used for insulation purposesin building construction and in the manufacture of energy efficientelectrical appliances. In the construction industry, polyurethane(polyisocyanurate) board stock is used in roofing and siding for itsinsulation and load-carrying capabilities. Poured and sprayedpolyurethane foams are also used in construction. Sprayed polyurethanefoams are widely used for insulating large structures such as storagetanks, etc. Pour-in-place polyurethane foams are used, for example, inappliances such as refrigerators and freezers plus they are used inmaking refrigerated trucks and railcars.

All of these various types of polyrethane foams require expansion agents(blowing agents) for their manufacture. Insulating foams depend on theuse of halocarbon blowing agents, not only to foam the polymer, butprimarily for their low vapor thermal conductivity, a very importantcharacteristic for insulation value. Historically, polyurethane foamsare made with CFC-11 (CFCl₃) as the primary blowing agent.

A second important type of insulating foam is phenolic foam. Thesefoams, which have very attractive flammability characteristics, aregenerally made with CFC-11 and CFC-113(1,1,2-trichloro-1,2,2-trifluoroethane) blowing agents.

A third type of insulating foam is thermoplastic foam, primarilypolystyrene foam. Polyolefin foams (polyethylene and polypropylene) arewidely used in packaging. These thermoplastic foams are generally madewith CFC-12.

Many smaller scale hermetically sealed, refrigeration systems, such asthose used in refrigerators or window and auto air conditioners, usedichlorodifluoromethane (CFC-12) as the refrigerant. Larger scalecentrifugal refrigeration equipment, such as those used for industrialscale cooling, e.g., commercial office buildings, generally employtrichlorofluoromethane (CFC-11) or 1,1,2-trichlorotrifluoroethane(CFC-113) as the refrigerants of choice. Azeotropic mixtures, with theirconstant boiling points and compositions have also been found to be veryuseful as substitute refrigerants, for many of these applications.

Aerosol products have employed both individual halocarbons andhalocarbon blends as propellant vapor pressure attenuators, in aerosolsystems. Azeotropic mixtures, with their constant compositions and vaporpressures would be very useful as solvents and propellants in aerosolsystems.

Some of the chlorofluorocarbons which are currently used for cleaningand other applications have been theoretically linked to depletion ofthe earth's ozone layer. As early as the mid-1970's, it was known thatintroduction of hydrogen into the chemical structure of previouslyfully-halogenated chlorofluorocarbons reduced the chemical stability ofthese compounds. Hence, these now destabilized compounds would beexpected to degrade in the lower atmosphere and not reach thestratospheric ozone layer intact. What is also needed, therefore, aresubstitute chlorofluorocarbons which have low theoretical ozonedepletion potentials.

Unfortunately, as recognized in the art, it is not possible to predictthe formation of azeotropes. This fact obviously complicates the searchfor new azeotropic compositions, which have application in the field.Nevertheless, there is a constant effort in the art to discover newazeotropic compositions, which have desirable solvency characteristicsand particularly greater versatilities in solvency power.

INVENTION SUMMARY

According to the present invention, azeotropic compositions have beendiscovered comprising admixtures of1,1,1,2,3,4,4,5,5,5-decafluoropentane effective amounts of (43-10 mee)and trans 1,2-dichloroethylene with an alcohol from the group consistingof methanol or ethanol. More specifically, the azeotropic mixtures are:an admixture of about 55-65 weight percent 43-10 mee and about 32.5-40weight percent trans 1,2-dichloroethylene and about 2.5-5 weight percentmethanol; and an admixture of about 59-67 weight percent 43-10 mee andabout 31.5-38 weight percent trans 1,2-dichloroethylene and about 0.5-3weight percent ethanol.

The preparation of 1,1,1,2,3,4,4,5,5,5-decafluoropentane from anunsaturated intermediate is disclosed in CR-8898, filed on even dateherewith by C. G. Krespan and V. N. M. Rao. The preparation of theunsaturated intermediate is disclosed in CR-8897, filed on even dateherewith by C. G. Krespan. The disclosures of both of these applicationsare hereby incorporated by reference.

The present invention provides nonflammable azeotropic compositionswhich are well suited for solvent cleaning applications.

The compositions of the invention can further be used as refrigerants inexisting refrigeration equipment, e.g., designed to use CFC-12 or F-11.They are useful in compression cycle applications including airconditioner and heat pump systems for producing both cooling andheating. The new refrigerant mixtures can be used in refrigerationapplications such as described in U.S. Pat. No. 4,482,465 to Gray.

DETAILED DESCRIPTION OF THE INVENTION

The compositions of the instant invention comprise admixture ofeffective amounts of 43-10 mee (CF₃ CHFCHFCF₂ CF₃, boiling point=50° C.)and trans 1,2-dichloroethylene (CHCl═CHCl, boiling point=48° C.) with analcohol selected from the group consisting of methanol (CH₃ OH, boilingpoint=64.6° C.) or ethanol (CH₃ CH₂ OH, boiling point=78.4° C.) to forman azeotropic composition.

By azeotropic composition is meant a constant boiling liquid admixtureof three or more substances, whose admixture behaves as a singlesubstance, in that the vapor, produced by partial evaporation ordistillation of the liquid has the same composition as the liquid, i.e.,the admixture distills without substantial composition change. Constantboiling compositions, which are characterized as azeotropic, exhibiteither a maximum or minimum boiling point, as compared with that of thenonazeotropic mixtures of the same substances.

By effective amount is meant the amount of each component of the instantinvention admixture, which when combined, results in the formation ofthe azeotropic composition of the instant invention.

The language "an azeotropic composition consisting essentially of . . ." is intended to include mixtures which contain all the components ofthe azeotrope of this invention (in any amounts) and which, iffractionally distilled, would produce an azeotrope containing all thecomponents of this invention in at least one fraction, alone or incombination with another compounds, e.g., one distills at substantiallythe same temperature as said fraction and does not significantly affectthe azeotropic character of the composition. It is possible tocharacterize, in effect, a constant boiling admixture, which may appearunder many guises, depending upon the conditions chosen, by any ofseveral criteria:

The composition can be defined as an azeotrope of A, B and C, since thevery term "azeotrope" is at once both definitive and limitative, andrequires that effective amounts A, B and C form this unique compositionof matter, which is a constant boiling admixture.

It is well known by those skilled in the art that at differentpressures, the composition of a given azeotrope will vary--at least tosome degree--and changes in pressure will also change--at least to somedegree--the boiling point temperature. Thus an azeotrope of A, B and Crepresents a unique type of relationship but with a variable compositionwhich depends on temperature and/or pressure. Therefore compositionalranges, rather than fixed compositions, are often used to defineazeotropes.

The composition can be defined as a particular weight percentrelationship or mole percent relationship of A, B and C, whilerecognizing that such specific values point out only one particular suchrelationship and that in actuality, a series of such relationships,represented by A, B and C actually exist for a given azeotrope, variedby the influence of pressure.

Azeotrope A, B and C can be characterized by defining the composition asan azeotrope characterized by a boiling point at a given pressure, thusgiving identifying characteristics without unduly limiting the scope ofthe invention by a specific numerical composition, which is limited byand is only as accurate as the analytical equipment available.

Ternary mixtures of 55-65 (preferably 58-64) weight percent 43-10 meeand 32.5-40 (preferably 34-38) weight percent trans 1,2-dichloroethyleneand 2.5-5 (preferably 3-4) weight percent methanol are characterized asazeotropic, in that mixtures within this range exhibit a substantiallyconstant boiling point at constant pressure. Being substantiallyconstant boiling, the mixtures do not tend to fractionate to any greatextent upon evaporation.

After evaporation, only a small difference exists between thecomposition of the vapor and the composition of the initial liquidphase. This difference is such that the compositions of the vapor andliquid phases are considered substantially identical.

Accordingly, any mixture within this range exhibits properties which arecharacteristic of a true ternary azeotrope. The ternary compositionconsisting of about 60.5 weight percent 43-10 mee, and about 36.2 weightpercent trans 1,2-dichloroethylene and about 3.3 weight percent methanolhas been established, within the accuracy of the fractional distillationmethod, as a true ternary azeotrope, boiling at about 35.3° C., atsubstantially atmospheric pressure.

Also according to the instant invention, ternary mixtures of 59-67(preferably 61-66) weight percent 43-10 mee and 31.5-38 (preferably33.5-37) weight percent trans 1,2-dichloroethylene and 0.5-3 (preferably0.5-2) weight percent ethanol are characterized as azeotropic, in thatmixtures within this range exhibit a substantially constant boilingpoint at constant pressure. Being substantially constant boiling, themixtures do not tend to fractionate to any great extent uponevaporation.

After evaporation, only a small difference exists between thecomposition of the vapor and the compostion of the initial liquid phase.This difference is such that the compositions of the vapor and liquidphases are considered substantially identical.

Accordingly, any mixture within this range exhibits properties which arecharacteristic of a true ternary azeotrope. The ternary compositionconsisting of about 64 weight percent 43-10 mee, and about 35 weightpercent trans 1,2-dichloroethylene and about 1 weight percent ethanolhas been established, within the accuracy of the fractional distillationmethod, as a true ternary azeotrope, boiling at about 35.1° C., atsubstantially.

The aforestated azeotropes have low ozone-depletion potentials and areexpected to decompose almost completely, prior to reaching thestratosphere.

The azeotropic compositions of the instant invention permit easyrecovery and reuse of the solvent from vapor defluxing and degreasingoperations because of their azeotropic natures. As an example, theazeotropic mixtures of this invention can be used in cleaning processessuch as described in U.S. Pat. No. 3,881,949, or as a buffing abrasivedetergent.

In addition, the mixtures are useful as resist developers, wherechlorine-type developers would be used, and as resist stripping agentswith the addition of appropriate halocarbons.

Another aspect of the invention is a refrigeration method whichcomprises condensing a refrigerant composition of the invention andthereafter evaporating it in the vicinity of a body to be cooled.Similarly, still another aspect of the invention is a method for heatingwhich comprises condensing the invention refrigerant in the vicinity ofa body to be heated and thereafter evaporating the refrigerant.

A further aspect of the invention includes aerosol compositionscomprising an active agent and a propellant, wherein the propellant isan azeotropic mixture of the invention; and the production of thesecompositions by combining said ingredients. The invention furthercomprises cleaning solvent compositions comprising the azeotropicmixtures of the invention.

The azeotropic compositions of the instant invention can be prepared byany convenient method including mixing or combining the desiredcomponent amounts. A preferred method is to weigh the desired componentamounts and thereafter combine them in an appropriate container.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The following preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the disclosure in any way whatsoever.

In the foregoing and in the following examples, all temperatures are setforth uncorrected in degrees Celsius and unless otherwise indicated, allparts and percentages are by weight.

The 1,1,1,2,3,4,4,5,5,5-decafluoropentane of this invention may beprepared by starting with materials described in U.S. patent applicationSer. No. 07/595,839 which is hereby incorporated by reference in itsentirely. According to the teachings therein, polyfluoroolefins havingat least 5 carbon atoms may be manufactured by reacting together twoselected polyfluoroolefins in the presence of a catalyst of the formulaAlX₃ where X is one or more of F, Cl or Br (provided that X is notentirely F). As exemplified by Example 4 herein, a five carbonperfluoroolefinic starting material may be prepared by the reaction ofhexafluoropropene (HFP) with tetrafluoroethylene (TFE). A six carbonperfluoro-olefinic starting material may be prepared by the reaction,substantially according to the procedure of Example 4, of1,1,1,4,4,4-hexafluoro-2,3-dichloro-2-butene with TFE to yield anintermediate product comprising perfluoro-2,3-dichloro-2-hexene whichmay then be converted to perfluoro-2-hexene by reaction with potassiumfluoride in refluxing N-methyl pyrolidone. A mixture of seven carbonperfluoroolefinic starting materials may be prepared by the reaction,substantially according to the procedure of Example 4, ofhexafluoro-propene with 2 moles of TFE.

The CF₃ CHFCHFCF₂ CF₃ of this invention may be prepared by a processwhich comprises the step of reacting an olefinic starting materialprepared or described above in the vapor phase with hydrogen over ametal catalyst from the palladium group. The olefinic starting materialfor this process has the same number of carbon atoms as the desireddihydropolyfluoroalkanes and may be CF₃ CF═CFCF₂ CF₃, and has itsolefinic bond between the carbon atoms which correspond to the carbonswhich bear the hydrogen in said dihydropolyfluoroalkane.

Unsupported metal catalysts and supported metal catalysts wherein themetal is palladium, rhodium, or ruthenium are suitable for use in thisprocess. supports such as carbon or alumina may be employed. Palladiumon alumina is the preferred catalyst.

The vapor phase reduction can be carried out at temperatures in therange of from about 50° C. to about 225° C.; the preferred temperaturerange is from about 100° C. to about 200° C. The pressure of thehydrogenation may vary widely from less than 1 atmosphere to 20 or moreatmospheres. The molar ratio of hydrogen to olefinic starting materialfor this process is preferably between about 0.5:1 and 4:1, and is morepreferably between about 0.5:1 and 1.5:1.

Processes for the preparation of CF₃ CHFCHFCF₂ CF₃ are exemplified inExamples 5 and 6 herein.

The entire disclosure of all applications, patents and publications,cited above and below, are hereby incorporated by reference.

EXAMPLE 1

A solution which contained 66.1 weight percent1,1,1,2,3,4,4,5,5,5-decafluoropentane (43-10 mee), 30.9 weight percenttrans 1,2-dichloroethylene and 3.0 weight percent methanol was preparedin a suitable container and mixed thoroughly.

The solution was distilled in a Perkin-Elmer Mode 251 AutoannularSpinning Band Still (200 plate fractionating capability), using a 20:1reflux to take-off ratio. Head and pot temperatures were adjusted to 760mm Hg pressure. Head temperatures were read directly to 0.1° C.Distillated compositions were determined by gas chromatography. Resultsobtained are summarized in Table 1.

                  TABLE 1                                                         ______________________________________                                        DISTILLATION OF:                                                              (66.1 + 30.9 + 3.0)                                                           43-10 mee (43-10)                                                             TRANS 1,2-DICHLOROETHYLENE (TRANS),                                           AND METHANOL (MEOH)                                                                        WT. %                                                                         DISTILLED  WEIGHT                                                TEMP., °C.                                                                          OR RE-     PERCENTAGES                                           CUTS  POT    HEAD    COVERED  43-10                                                                              TRANS  MEOH                                ______________________________________                                        11    36.7   34.8    53.9     61.38                                                                              35.25  3.37                                12    36.8   34.8    56.8     60.98                                                                              35.71  3.31                                13    37.5   34.9    61.4     62.91                                                                              33.93  3.16                                14    37.9   35.4    66.8     59.85                                                                              36.87  3.28                                15    38.6   35.4    70.3     59.61                                                                              37.02  3.37                                16    38.6   35.5    73.8     59.32                                                                              37.37  3.31                                17    42.0   35.9    78.0     59.57                                                                              37.13  3.30                                18    46.0   35.9    80.8     60.11                                                                              36.26  3.63                                HEEL  --     --      87.1     96.27                                                                               2.27  1.46                                ______________________________________                                    

Analysis of the above data indicates very small differences between headtemperatures and distillate compositions, as the distillationprogressed. A statistical analysis of the data indicates that the trueternary azeotrope of 43-10 mee, trans 1,2-dichloroethylene and methanolhas the following characteristics at atmospheric pressure (99 percentconfidence limits):

43-10 mee=60.5±4.1 wt. %

trans 1,2-dichlorethylene=36.2±3.9 wt. %

methanol=3.3±0.1 wt. %

Boiling point, ° C.=35.3±1.5

EXAMPLE 2

A solution which contained 64.7 weight percent (43-10 mee), 32.8 weightpercent trans 1,2-dichloroethylene and 2.5 weight percent ethanol wasprepared in a suitable container and mixed thoroughly.

The solution was distilled in a Perkin Elmer Mode 251 AutoannularSpinning Band Still (200 plate fractionating capability), using a 15:1reflux ratio to take-off ratio. Head and pot temperatures were readdirectly to 0.1° C. All temperatures were adjusted to 760 mm pressure.Distillate compositions were determined by gas chromatography. Resultsobtained are summarized in Table 2.

                  TABLE 2                                                         ______________________________________                                        DISTILLATION OF:                                                              (64.7 + 32.8 + 2.5)                                                           43-10 mee (43-10),                                                            TRANS 1,2-DICHLOROETHYLENE (TRANS)                                            AND ETHANOL (ETOH)                                                                         WT. %                                                                         DISTILLED   WEIGHT                                               TEMP., °C.                                                                          OR          PERCENTAGES                                          CUTS  POT    HEAD    RECOVERED 43-10                                                                              TRANS  ETOH                               ______________________________________                                        1     37.9   35.0    10.9      64.58                                                                              34.45  0.97                               2     37.9   35.0    16.0      64.06                                                                              34.91  1.03                               3     37.9   35.0    19.4      63.81                                                                              35.14  1.05                               4     38.0   35.1    24.3      63.74                                                                              35.22  1.04                               5     38.2   35.0    29.4      65.08                                                                              33.85  1.07                               6     38.3   35.0    35.4      64.28                                                                              34.76  0.96                               7     38.5   35.1    47.9      63.94                                                                              35.07  0.99                               8     38.6   35.1    53.9      63.42                                                                              35.61  0.97                               9     38.8   35.1    61.7      63.50                                                                              35.57  0.93                               10    39.0   35.2    72.0      63.08                                                                              35.91  1.01                               HEEL  --     --      --        82.45                                                                               7.91  9.64                               ______________________________________                                    

Analysis of the above data indicates very small differences between headtemperatures and distillate compositions, as the distillationprogressed. A statistical analysis of the data indicates that the trueternary azeotrope of 43-10 mee, trans 1,2-dichloroethylene and ethanolhas the following characteristics at atmospheric pressure (99 percentconfidence limits):

43-10 mee=64.0±1.9 wt. %

trans 1,2-dichloroethylene=35.0±1.9 wt. %

ethanol=1.0±0.2 wt. %

Boiling point, ° C.=35.1±0.2

EXAMPLE 3

Several single sided circuit boards were coated with activated rosinflux and soldered by passing the boards over a preheater, to obtain topside board temperatures of approximately 200° F. (93° C.), and thenthrough 500° F. (260° C.) molten solder. The soldered boards weredefluxed separately, with the azeotropic mixtures cited in Examples 1and 2 above, by suspending a circuit board, first, for three minutes inthe boiling sump, which contained the azeotropic mixture, then, for oneminute in the rinse sump, which contained the same azeotropic mixture,and finally, for one minute in the solvent vapor above the boiling sump.The boards cleaned in each azeotropic mixture had no visible residueremaining thereon.

EXAMPLE 4 Preparation of CF₃ CF═CF₂ CF₃ (F-Pentene-2)

A 400-mL metal tube charged at -20° C. with 8.0 g of AlF₂.8 Cl₀.2(prepared from AlCl₃), 75 g (0.50 mol) of hexafluoropropene, and 50 g(0.50 mol) of tetrafluoroethylene was shaken for 30 min. while thetemperature rose quickly to 20° C. and the pressure dropped to 8 psi.Distillation of the product afforded 88.0 g (70%) of F-pentene-2, b.p.23°-26° C., identified by IR, NMR and GC/MS. NMR showed the product tobe 89% trans-isomer and 11% cis-isomer.

EXAMPLE 5 Vapor Phase Reduction of CF₃ CF═CFCF₂ CF₃

A 6"×1/2" O. D. Hastelloy tube was charged with 10.0 g of 0.5% palladiumon 5×8 mesh alumina spheres. This was a commercial sample from Calsicatwhich was reduced with hydrogen prior to use. Co-fed to the reactor werevaporized perfluoropentene-2 (2 mL/hr as liquid) and hydrogen (20mL/min). Product stream leaving the reactor was analyzed by on-line GCand on-line MS, the product then being collected in a -80° C. trapduring the run. At temperatures of 100°-200° C., conversions were 96-99%with yields of perfluoro-2H,3H-pentane consistently 95% or better overthe temperature range. The level of trihydro by-product was about 1%.Product, bp 50-55% ° C., easily obtained pure by a simple fractionation,was shown by GC and NMR analyses to have a ratio of diastereomers ofabout 90:10.

EXAMPLE 6 Reduction of CF₃ CF═CFCF₂ CF₃

Reduction of 22.7 g (0.091 mol) of perfluoropentene-2 with 2.0 g of 5%Pd on carbon in 100 mL of toluene was carried out at 25° C. under ca.20-50 psi of hydrogen until hydrogen absorption fell to 0.3 psi/hour.Distillation served to isolate volatiles, bp 25°-62° C., 18.3 g, whichcontained 65 wt- % of pentanes composed of 94:6 mol-ratio of dihydro- totrihydropentanes. The perfluoro-2H,3H-pentane consisted of diastereomersin a 97:3 ration, an especially high selectivity.

This reaction demonstrated the unusually high selectivity fordihydrogenation of a perfluorinated linear internal olefin and, inaddition, striking selectivity for formation of only one diastereomericdihydro product, when the metal-catalyzed reduction is carried out innonpolar medium.

I claim:
 1. An azeotropic composition consisting essentially of:(a)55-65 weight percent 1,1,1,2,3,4,4,5,5,5-decafluoropentane, 32.5-40weight percent trans 1,2-dichloroethylene, and 2.5-5 weight percentmethanol, wherein the composition has a boiling point of about 35.3° C.when the pressure is adjusted to substantially atmospheric pressure; or(b) 59-67 weight percent 1,1,1,2,3,4,4,5,5,5-decafluoropentane, 31.5-38weight percent trans 1,2-dichloroethylene, and about 0.5-3 weightpercent ethanol, wherein the composition has a boiling point of about35.1° C. when the pressure is adjusted to substantially atmosphericpressure.
 2. The azeotropic composition of claim 1, consistingessentially of about 55-65 weight percent1,1,1,2,3,4,4,5,5,5-decafluoropentane, about 32.5-40 weight percenttrans 1,2-dichloroethylene and about 2.5-5 weight percent methanol. 3.The azeotropic composition of claim 2 consisting essentially of 58-64weight percent 1,1,1,2,3,4,4,5,5,5-decafluoropentane, 34-38 weightpercent trans 1,2-dichloroethylene and 3-4 weight percent methanol. 4.The azeotropic composition of claim 3, consisting essentially of about60.5 weight percent 1,1,1,2,3,4,4,5,5,5-decafluoropentane, about 36.2weight percent trans 1,2-dichloroethylene and about 3.3 weight percentmethanol.
 5. The azeotropic composition of claim 1, consistingessentially of about 59-67 weight percent1,1,1,2,3,4,4,5,5,5-decafluoropentane, about 31.5-38 weight percenttrans 1,2-dichloroethylene and about 0.5-3 weight percent ethanol. 6.The azeotropic composition of claim 5 consisting essentially of 61-66weight percent 1,1,1,2,3,4,4,5,5,5-decafluoropentane, 33.5-37 weightpercent trans 1,2-dichloroethylene and 0.5-2 weight percent ethanol. 7.The azeotropic composition of claim 6, consisting essentially of about64 weight percent 1,1,1,2,3,4,4,5,5,5-decafluoropentane, about 35.0weight percent trans 1,2-dichloroethylene and about 1.0 weight percentethanol.
 8. A process for producing a refrigeration which comprisesevaporating a mixture of claim 1 in the vicinity of a body to be cooled.9. A process for producing heat which comprises condensing a compositionof claim 1 in the vicinity of a body to be heated.
 10. In a process forpreparing a polymer foam comprising expanding a polymer with a blowingagent, the improvement wherein the blowing agent is a composition ofclaim
 1. 11. In an aerosol composition comprising a propellant and anactive agent, the improvement wherein the propellant is a composition ofclaim
 1. 12. A process for preparing aerosol formulations comprisingcondensing an active ingredient in an aerosol container with aneffective amount of the composition of claim 1 as a propellant.
 13. Aprocess for cleaning a solid surface which comprises treating saidsurface with the azeotrope or azeotrope-like compositions of claim 1.14. The process of claim 12, wherein the solid surface is a printedcircuit board contaminated with flux and flux-residues.
 15. The processof claim 13, wherein the solid surface is a metal.